There are things that are worthless-- that provide no value. There are also things that are worse than worthless-- things that provide negative value. I have found that people sometimes confuse the latter for the former, which can carry potentially dire consequences.
One simple example of this is in fencing. I once fenced with an opponent who put a bit of an unnecessary twirl on his blade when recovering from each parry. After our bout, one of the spectators pointed out that there wasn't any point to the twirls and that my opponent would improve by simply not doing them anymore. My opponent claimed that, even if the twirls were unnecessary, at worst they were merely an aesthetic preference that was useless but not actually harmful.
However, the observer explained that any unnecessary movement is harmful in fencing, because it spends time and energy that could be put to better use-- even if that use is just recovering a split second faster! [1]
During our bout, I indeed scored at least one touch because my opponent's twirling recovery was slower than a less flashy standard movement. That touch could well be the difference between victory and defeat; in a real sword fight, it could be the difference between life and death.
This isn't, of course, to say that everything unnecessary is damaging. There are many things that we can simply be indifferent towards. If I am about to go and fence a bout, the color of the shirt that I wear under my jacket is of no concern to me-- but if I had spent significant time before the bout debating over what shirt to wear instead of training, it would become a damaging detail rather than a meaningless one.
In other words, the real damage is dealt when something is not only unnecessary, but consumes resources that could instead be used for productive tasks. We see this relatively easily when it comes to matters of money, but when it comes to wastes of time and effort, many fail to make the inductive leap.
[1] Miyamoto Musashi agrees:
The primary thing when you take a sword in your hands is your intention to cut the enemy, whatever the means. Whenever you parry, hit, spring, strike or touch the enemy's cutting sword, you must cut the enemy in the same movement. It is essential to attain this. If you think only of hitting, springing, striking or touching the enemy, you will not be able actually to cut him. More than anything, you must be thinking of carrying your movement through to cutting him. You must thoroughly research this.
Well, one short answer is "not much anymore, which is why I hadn't played in a long time before coming back recently".
Another short answer is "I often say that WoW is a glorified IRC server; I mostly sign on to socialize with guild mates".
There's a longer answer, though, and it's this:
Hunter is one class. I play others. Actually, I've always primarily played tanks, and tank classes have never been anywhere near so monotonous to play.
Even in 2006-2008 (the period of the Burning Crusade expansion, when the "only hit Steady Shot" approach worked), to say that hitting that one button repeatedly is the only thing you needed to do to win was a bit of a simplification. True, your rotation was as simple as can be; but there are other aspects of correct play, both in-the-moment (DPS cooldown timing; mana management; positioning and other things to do with fight mechanics; pet control) and during-downtime (gearing; pet optimization; writing appropriate macros). I can honestly say that playing a hunter in raids at this time was genuinely and unreservedly fun (in addition to the aforementioned other aspects of play, this was partly because being the best at DPS was very satisfying and rewarding).
The game content itself (story, characters, fight mechanics, etc.) is interesting (though this is less true recently, imo).
So, while I understand and acknowledge your reasons for not playing (and indeed they were my own reasons as well for a long time), I disagree with taking my aforementioned hunter experience as a strong example of WoW being boring.
Acknowledged. I mistakenly assumed that your description of Hunter DPS mechanics was meant to be a current and representative example of the game.